Green synthesis method of nanoparticles has captivated considerable attentiveness in recent years due to its eco-friendly and non-consumptive properties. The aim of this research is to synthesize and characterize magnesium oxide nanoparticles (MgO-NPs) nanoparticles using orange and coconut extracts as a reducing agent. A plant extract mixed with metal salt solution in ratio was synthesized under alkaline condition (pH 9) with continuous stirring for 3 hours, using the bottom-up approach. The MgO NPs was synthesized by precipitation method. Several analytical techniques were used to characterize the synthesized MgO-NPs using techniques such as X-ray diffractometer (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), Thermogravimetric analysis (TGA) and Brunauer-Emmett-Teller (BET). The results revealed that the synthesized orange and coconut shaft MgO-NPs exhibited an average particle sizes of X and Y nm. The XRD confirmed the presence of six mineral composition for orange peel; Pericles (47 %), Quartz (25 %), Zincite (15%), Chloragyrite (8 %), Woodhouseite (3 %), Tenorite, Syn (2 %) in the MgO NPs and Coconut Mesocarp (shaft) composition are as follow brucite 34.5 %, hanksite 28.8 %, siderite, Mg-be 24 %, chlorargyrite 1.9 %, Quartz 4.6 % and woodhouseite 3 %. The FTIR spectroscopy for the orange peel indicated the presence of the functional groups in which the spectral identified the peaks of functional groups O-H, C=O, C-C, C-O-C, C-O, Mg-O, Mg-O-Mg and the Coconut Mesocarp spectra also identified similar functional groups. SEM shows the morphology of the small, irregular particle sizes with some agglomeration due to O-H. TGA shows the thermal stability of the MgO nanoparticles which indicated increase in the temperature lead to a decrease in the weight percentage. BET result shows the surface area was 237.5 m2/g and 235.5 m2/g for the orange peel and coconut shaft MgO-NPs respectively. This eco-friendly method does not only provide a sustainable approach to nanoparticle synthesis but also highlights the potential of agricultural waste as a valuable resource in the nanotechnology applications.